Can't connect to Mongo Docker Container From Node Container on M1 Mac

I am currently trying to connect my Node container to my Mongo container using an M1 chip. Many have said that you can’t run Mongo 4.9+ on an M1 Mac as there is no support for AVR. I can’t say why but on my M1 mongo runs just fine. I can connect to the container via Mongo Compass using mongo://mongo:27017. Additionally if I run my Node app outside of docker I can connect to the Mongo container just fine using the same connection string. But for some reason I cannot connect the containerized node app to the containerized Mongo service.

Dockerfile

 FROM node:12

# Create app directory
WORKDIR /usr/src/app

# Copy dependencies 
COPY package*.json ./

# Install dependencies 
RUN npm install

RUN npm ci --only=production

# Bundle app source
COPY . .

EXPOSE 3000
CMD [ "node", "server.js" ]

docker-compose.yml

version: "2"
services:
  web:
    build: .
    ports:
    - "3000:3000"
    depends_on:
    - mongo
  mongo:
    image: mongo
    ports:
    - "27017:27017"

Connection Method

/* Mongoose Connection */
const mongoose = require('mongoose')

mongoose.Promise = global.Promise
mongoose.connect(
  'mongodb://mongo:27017',
  { useNewUrlParser: true }
)
mongoose.connection.on('error', console.error.bind(console, 'MongoDB connection 

Error:’))

mongoose.set('debug', true)

module.exports = mongoose.connection

server.js

require('dotenv').config();
const express = require('express')
const app = express()
const bodyParser = require('body-parser')
const expressValidator = require('express-validator')
var cookieParser = require('cookie-parser');
const jwt = require('jsonwebtoken');
app.use(cookieParser()); // Add this after you initialize express.


// db
require('./data/reddit-db')

// set db
const exphbs = require('express-handlebars')

// body parser
app.use(bodyParser.json())
app.use(bodyParser.urlencoded({ extended: false }))
app.use(expressValidator())

app.engine('handlebars', exphbs({ defaultLayout: 'main' }))
app.set('view engine', 'handlebars')


var checkAuth = (req, res, next) => {
  console.log("Checking authentication");
  if (typeof req.cookies.nToken === "undefined" || req.cookies.nToken === null) {
    req.user = null;
  } else {
    var token = req.cookies.nToken;
    var decodedToken = jwt.decode(token, { complete: true }) || {};
    req.user = decodedToken.payload;
  }

  next();
};
app.use(checkAuth);

// routes
require('./controllers/posts.js')(app)

require('./controllers/comments.js')(app)

require('./controllers/auth.js')(app)

require('./controllers/replies.js')(app)




// Start Server
app.listen(3000, () => {
  console.log('Reddit Search listening on port localhost:3000!');
});

module.exports = app

Error

redditjspart2-web-1    | Reddit Search listening on port localhost:3000!
redditjspart2-web-1    | MongoDB connection Error: { MongoNetworkError: failed to connect to server [127.0.0.1:27017] on first connect [MongoNetworkError: connect ECONNREFUSED 127.0.0.1:27017]
redditjspart2-web-1    |     at Pool.<anonymous> (/usr/src/app/node_modules/mongoose/node_modules/mongodb/lib/core/topologies/server.js:438:11)
redditjspart2-web-1    |     at Pool.emit (events.js:198:13)
redditjspart2-web-1    |     at createConnection (/usr/src/app/node_modules/mongoose/node_modules/mongodb/lib/core/connection/pool.js:561:14)
redditjspart2-web-1    |     at connect (/usr/src/app/node_modules/mongoose/node_modules/mongodb/lib/core/connection/pool.js:994:11)
redditjspart2-web-1    |     at makeConnection (/usr/src/app/node_modules/mongoose/node_modules/mongodb/lib/core/connection/connect.js:31:7)
redditjspart2-web-1    |     at callback (/usr/src/app/node_modules/mongoose/node_modules/mongodb/lib/core/connection/connect.js:264:5)
redditjspart2-web-1    |     at Socket.err (/usr/src/app/node_modules/mongoose/node_modules/mongodb/lib/core/connection/connect.js:294:7)
redditjspart2-web-1    |     at Object.onceWrapper (events.js:286:20)
redditjspart2-web-1    |     at Socket.emit (events.js:198:13)
redditjspart2-web-1    |     at emitErrorNT (internal/streams/destroy.js:91:8)
redditjspart2-web-1    |     at emitErrorAndCloseNT (internal/streams/destroy.js:59:3)
redditjspart2-web-1    |     at process._tickCallback (internal/process/next_tick.js:63:19)
redditjspart2-web-1    |   name: 'MongoNetworkError',
redditjspart2-web-1    |   [Symbol(mongoErrorContextSymbol)]: {} }

What I Have Tried:

• Running the same repo on an intel mac (works flawlessly)
• Changing the connection string IP (mongo, localhost, 127.0.0.1)
• Using a docker network with the bridge driver and using the assigned ip in the connection string
• pinging mongo from inside Node container (this works and all packets are received)

The error says that it’s trying to connect to 127.0.0.1:27017 which means it is properly resolving the hostname and mapping it to my localhost. So the Node container is definitely able to find it. This also makes sense because I can still ping the Mongo container from the Node container as I mentioned earlier. Looks like Mongo is just refusing to connect for some reason.

I am really struggling to figure out why this would be the case. The link to my repo is public and you can find it on github here: https://github.com/lukeaparker/reddit.jspart2

Thanks so so much!!